Question

can you give me every single questions answers with reference

1. What is genetics?

2. What is a karyotype?

3. What are chromosomes? (Include how many chromosomes humans have and what autosomes and sex chromosomes are.)

4. What is a gene?

5. What do the terms “allele” and “homologue” mean?

6. What do we mean by the following terms:
   1. Homozygous trait
   2. Heterozygous trait
   3. Dominant gene
   4. Recessive gene

Answer 1

1. Genetics is the study of hereditary of characters from one generation to another generation. In other words, genetics deals about why we have some characters similar to our father, mother or forefathers.

2. The image which contains the number and visual appearance of all chromosomes of an individual, that is called as karyotype.

3. The thread like structure consists of nucleic acids and proteins and which also controls all characteristics of an organism by the genes present in it, is known as chromosome. The humans have 46 chromosomes or 23 pairs of chromosomes. The chromosomes which are responsible for somatic characters are known as autosomes and the chromosomes which controls the sexual characters or behavior of an individual ( the characters by which we can differentiate individuals into male and female) are known as sex chromosomes. Humans have 44 or 22 pairs of autosomes and 2 or one pair of sex chromosome (XX in female and XY in male).

4. Gene is the structural and functional unit of hereditary. The genes synthesizes proteins which controls the characters of an individual.

5. A specific form of gene is known as allele. For example the height of a pea plant has two alleles, the tall allele and the dwarf allele.

When two similar alleles are found in an individual, it is called as homologue. For example, TT allelic combination is called as homologue responsible for tall pea plant, but the tt allelic combination is responsible for dwarf pea plant and is also called as homologue. As in both cases similar alleles are found. But when the allele combination is Tt, although it results in tall pea plant, but it is not called as homologue, as this allelic combination is heterozygous.

A. When the homologous chromosome contains both similar alleles, it is called as homozygous trait. For example, TT allelic combination is homozygous trait.

B. When two different alleles are found in the homologous chromosome, it is called as heterozygous trait. For example Tt allelic combination is called as heterozygous trait.

C. When one gene suppress the activity/ expression of another gene and express itself in the heterozygous condition, the gene which is expressed is called as dominant gene.

D. The gene which is suppressed/ masked by another gene in heterozygous condition, the gene which gets suppressed is called as recessive gene.

In pea plant, the height may be tall controlled by the allele T or dwarf controlled by the allele t. So, on heterozygous condition i.e.. Tt, the gene T express itself masking the effect of t gene and the plant becomes tall in height. Hence the gene responsible for tall pea plant is called as dominant gene, while the gene responsible for dwarf pea plant is called as recessive gene.